Sökning: "dust extinction"

Visar resultat 1 - 5 av 11 avhandlingar innehållade orden dust extinction.

  1. 1. Sources of Dust Extinction in Type Ia Supernovae : Measurements and constraints from X-rays to the Infrared

    Författare :Joel Johansson; Edvard Mörtsell; Ariel Goobar; Rahman Amanullah; Bruno Leibundgut; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; supernovae; interstellar dust; circumstellar dust; cosmology; fysik; Physics;

    Sammanfattning : The use of Type Ia supernovae (SNe Ia) as distance indicators is essential for studying the expansion history of the Universe and for exploring the nature of dark energy. However, a lack of understanding of the progenitor systems and the empirically derived colour-brightness corrections represent severe limitations for SNe Ia as cosmological probes. LÄS MER

  3. 2. Extinction in Molecular Clouds : Case of Barnard 335

    Författare :Sven Olofsson; Göran Olofsson; Kalevi Mattila; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ISM; interstellar medium; extinction; molecular cloud; Astronomy; astronomi; Astronomy; astronomi;

    Sammanfattning : The Bok globule B335 is a small molecular cloud in the solar neighbourhood near the galactic plane. The aim for this three-paper-study is to construct and analyze the extinction for this globule. The method we apply is to use the light from field stars behind the cloud in broadband filters ranging from UV to the mid-infrared. LÄS MER

  4. 3. Extragalactic extinction and spectral properties of Type Ia supernovae

    Författare :Linda Östman; Ariel Goobar; Avishay Gal-Yam; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Type Ia supernovae; cosmology; spectroscopy; dust extinction; quasars; axions; Physics; Fysik; fysik; Physics;

    Sammanfattning : The use of Type Ia supernovae as standardisable candles for probing cosmological parameters with high precision requires good knowledge about how the supernova light is affected along the line of sight and how the intrinsic brightness varies between objects. The work in this thesis addresses these topics. LÄS MER

  5. 4. The Circumstellar Environment of Type Ia Supernovae

    Författare :Raphael Ferretti; Rahman Amanullah; Ariel Goobar; Josh Simon; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Type Ia supernovae; extinction; supernova cosmology; fysik; Physics;

    Sammanfattning : Type Ia supernovae (SNe Ia) have proven to be extremely useful for measuring cosmological distances and were used for the discovery of the accelerated expansion of the universe. Although thousands of SNe Ia have been observed to date, many questions surrounding the physics of the explosions and the nature of their progenitor systems remain unanswered. LÄS MER

  7. 5. Transport of mineral dust into the Arctic : Evaluation of two reanalysis datasets of atmospheric composition

    Författare :Sebastian Böö; Annica M. L. Ekman; Adam Kristensson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Arktis; transport; damm; återanalys; reanalys; aerosol; meteorologi; Meteorology;

    Sammanfattning : The main purpose of this thesis is to examine the mineral dust aerosol transport into the Arctic. Two three-dimensional reanalysis datasets of atmospheric composition, the Copernicus Atmosphere Monitoring Service reanalysis (CAMSRA) and the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), are analyzed with regard to dust transport into the Arctic. LÄS MER